1、 Rec. ITU-R BS.450-3 1 RECOMMENDATION ITU-R BS.450-3 Transmission standards for FM sound broadcasting at VHF*(1982-1995-2001) The ITU Radiocommunication Assembly, recommends 1 that for FM sound broadcasting in band 8 (VHF) the following transmission standards should be used: 1 Monophonic transmissio
2、ns 1.1 Radio-frequency (RF) signal The RF signal consists of a carrier frequency-modulated by the sound signal to be transmitted, after pre-emphasis, with a maximum frequency deviation equal to: 75 kHz or 50 kHz. NOTE 1 In the West European countries and the United States of America, the maximum dev
3、iation is 75 kHz. In the ex-USSR and in some other European countries, it is 50 kHz. 1.2 Pre-emphasis of the sound signal The pre-emphasis characteristic of the sound signal is identical to the admittance-frequency curve of a parallel resistance-capacitance circuit having a time constant of: 50 s or
4、 75 s. NOTE 2 In Europe, the pre-emphasis is 50 s. In the United States of America, it is 75 s. 2 Stereophonic transmissions 2.1 Polar-modulation system 2.1.1 RF signal The RF signal consists of a carrier frequency-modulated by a baseband signal, known in this case as the stereophonic multiplex sign
5、al, with a maximum frequency deviation equal to: 75 kHz or 50 kHz (see Note 1, 1). 2.1.2 Stereophonic multiplex signal This signal is produced as follows: 2.1.2.1 A signal M is formed equal to one half of the sum of the left-hand signal, A, and the right-hand signal, B, corresponding to the two ster
6、eophonic channels. This signal, M, is pre-emphasized in the same way as monophonic signals (see 1). _ *Administrations are invited to supply further information on the system parameters, particularly concerning new tables on frequency tolerances. 2 Rec. ITU-R BS.450-3 NOTE 1 M is a compatible signal
7、 in the sense that the stereophonic transmission may be received by a monophonic receiver equipped for the same maximum frequency deviation and the same pre-emphasis. 2.1.2.2 A signal S is produced equal to one half of the difference between signals A and B mentioned above. This signal, S, is pre-em
8、phasized in the same way as signal M. The pre-emphasized signal, S, is used for the amplitude modulation of a sub-carrier at 31.25 kHz; the spectrum of the amplitude-modulated sub-carrier is formed so that the sub-carrier amplitude is reduced by 14 dB and the spectral components of the given modulat
9、ing signal appear to be transformed as follows: fff K4.6j54.6j1)(+= where f is equal to each frequency component (kHz). 2.1.2.3 The stereophonic multiplex signal is the sum of: the pre-emphasized signal, M; the sideband spectral components which are the product of amplitude-modulated unsuppressed ca
10、rrier by a pre-emphasized signal S additionally transformed from the law );( f K the sub-carrier with the amplitude reduced by 14 dB. 2.1.2.4 The amplitudes of the various components of the stereophonic multiplex signal, referred to the maximum amplitude of that signal (which corresponds to the maxi
11、mum frequency deviation) are: signal M : maximum value 80% (A and B being equal, and in phase); signal S : maximum value 80% (A and B being equal but of opposite phase); reduced sub-carrier at 31.25 kHz; maximum residual amplitude 20%. 2.1.2.5 The frequency modulation is arranged in such a way that
12、positive values of the multiplex signal correspond to a positive frequency deviation of the main carrier and negative values to negative frequency deviation. 2.2 Pilot-tone system 2.2.1 RF signal The RF signal consists of a carrier frequency-modulated by a baseband signal, known in this case as the
13、stereophonic multiplex signal, with a maximum frequency deviation equal to: 75 kHz or 50 kHz (see Note 1, 1). 2.2.2 Stereophonic multiplex signal This signal is produced as follows: 2.2.2.1 A signal M is formed equal to one half of the sum of the left-hand signal, A, and the right-hand signal, B, co
14、rresponding to the two stereophonic channels. This signal, M, is pre-emphasized in the same way as monophonic signals (see 1) (see Note 1, 2). 2.2.2.2 A signal S is produced equal to one half of the difference between signals A and B mentioned above. This signal, S, is pre-emphasized in the same way
15、 as signal M. The pre-emphasized signal, S, is used for the suppressed-carrier amplitude modulation of a sub-carrier at 38 kHz 4 Hz. Rec. ITU-R BS.450-3 3 NOTE 2 The same effect is obtained by pre-emphasizing the left-hand signal A and the right-hand signal B before encoding. For technical reasons t
16、his procedure is sometimes preferred. 2.2.2.3 The stereophonic multiplex signal is the sum of: the pre-emphasized signal, M; the sidebands of the suppressed sub-carrier amplitude modulated by the pre-emphasized signal, S; a pilot signal with a frequency of 19 kHz exactly one-half the sub-carrier fre
17、quency. 2.2.2.4 The amplitudes of the various components of the stereophonic multiplex signals referred to the maximum amplitude of that signal (which corresponds to the maximum frequency deviation) are: signal M : maximum value 90% (A and B being equal and in phase); signal S : maximum value of the
18、 sum of the amplitudes of the two sidebands: 90% (which corresponds to A and B being equal and of opposite phase); pilot signal: 8 to 10%; sub-carrier at 38 kHz suppressed: maximum residual amplitude 1%. 2.2.2.5 The relative phase of the pilot signal and the sub-carrier is such that, when the transm
19、itter is modulated by a multiplex signal for which A is positive and B = A, this signal crosses the time axis with a positive slope each time the pilot signal has an instantaneous value of zero. The phase tolerance of the pilot signal should not exceed 3 from the above state. Moreover, a positive va
20、lue of the multiplex signal corresponds to a positive frequency deviation of the main carrier. 2.2.3 Baseband signal in the case of a supplementary signal transmission If, in addition to the monophonic or stereophonic programme, a supplementary monophonic programme and/or supplementary information s
21、ignals are transmitted and the maximum frequency deviation is 75 kHz, the following additional conditions must be met: 2.2.3.1 The insertion of the supplementary programme or signals in the baseband signal must permit compatibility with existing receivers, i.e. these additional signals must not affe
22、ct the reception quality of the main monophonic or stereophonic programmes. 2.2.3.2 The baseband signal consists of the monophonic signal or stereophonic multiplex signal described above and having an amplitude of not less than 90% of that of the maximum permitted baseband signal value, and of the s
23、upplementary signals having a maximum amplitude of 10% of that value. 2.2.3.3 For a supplementary monophonic programme, the sub-carrier and its frequency deviation must be such that the corresponding instantaneous frequency of the signal remains between 53 and 76 kHz. 2.2.3.4 For supplementary infor
24、mation signals, the frequency of any additional sub-carrier must be between 15 and 23 kHz or between 53 and 76 kHz. 2.2.3.5 Under no circumstances may the maximum deviation of the main carrier by the total base signal exceed 75 kHz. 3 System parameters The system parameters used in different countri
25、es are given in Annex 1. 4 Rec. ITU-R BS.450-3ANNEX 1 Current sound broadcasting systems in the bands included in the Radio Regulations (RR) used in different countries/areas in the world 0450-01a-1+ + + + + + + + + +100 50 75200 75 75200 50 75200 75 75200 50 75100 50 75100 75 7575757575757575757550
26、75757575200 75200 75100 50200100 50200 75100 50100 50753010050100 5050100 50100 50 75100-108X769020106Modulation characteristicsTABLE 1aTerrestrial FM sound broadcasting (above 30 MHz)Polar-modulationsystemInformation related to current emission applicationsInternationalagreementsTransmitterfrequenc
27、ytolerances(RR Article 1)StereophonicMonophonicOthers88.0-10887.5-10876-87.573-7468-73OthersGeneva84Stockholm61Geneva60Frequency bands used(MHz)Polarization66-68Maximum frequencydeviation (kHz)Pilot-tonesystemHorizontalVerticalMixedCurrent requirementLong-termdesign objectiveCountry/Geographical are
28、aChannelspacing(kHz)( )1Germany (Federal Republic of)ArubaAustraliaBahamasBangladesh (Peoples Republic of)Cyprus (Republic of)Vatican City StateColombia (Republic of)Korea (Republic of)DenmarkEcuadorSpainUnited States of AmericaFinlandFranceGambia (Republic of the)Hungary (Republic of)India (Republi
29、c of)Iran (Islamic Republic of)ItalyExceptcases87.8108Pre-emphasis/de-emphasis(s)JapanRec. ITU-R BS.450-3 5 0450-01a-2+ + + + + + + + + + + + + + +100 50 753010050755075100 50 7575 75755010088-10050 50 75100 50 75100 50 75100 50 75200 50 75100 50 75100 50 75100 50 75100 50 75100 75 50100 50 75755010
30、0300 50 75100 50 75100 50 75301005075507573-7468-7366-68TABLE 1a (end)Modulation characteristicsPolar-modulationsystemInformation related to current emission applicationsInternationalagreementsTransmitterfrequencytolerances(RR Article 1)StereophonicMonophonicOthers88.0-10887.5-10876-87.5OthersGeneva
31、84Stockholm61Geneva60Frequency bands used(MHz)PolarizationMaximum frequencydeviation (kHz)Pilot-tonesystemHorizontalVerticalMixedCurrent requirementLong-termdesign objectiveCountry/Geographical areaChannelspacing(kHz)( )1SwedenSwitzerland (Confederation of)Turkeyfew fewPre-emphasis/de-emphasis(s)Sou
32、th Africa (Republic of)( ) For definition see Recommendation ITU-R BS.412. It is not meant the frequency spacing in overlapping service areas or tuning steps of the receiver.1Kuwait (State of)Lithuania (Republic of)Mali (Republic of)Morocco (Kingdom of)NorwayNew ZealandOman (Sultanate of)Papua New G
33、uineaNetherlands (Kingdom of the)Qatar (State of)Czech RepublicRwandese RepublicSenegal (Republic of)Singapore (Republic of)Slovenia (Republic of)fewUnited Kingdom of Great Britain andNorthern IrelandUkraineRec.ITU-RBS.4126Rec. ITU-R BS.450-3 TABLE 1b Terrestrial FM sound broadcasting (above 30 MHz)
34、 Information related to current receiving applications Additional information Oscillartor position Country/Geographical area Recommended or used IF (MHz) High Low Electromagnetic immunity requirements for receivers Compressor or compander systems Supplementary information Remarks Germany (Federal Re
35、public of) 10.7 + EN 55 020 Oui ARI, RDS Variable pre-emphasis at transmitter site in order to avoid excess of 75 kHz frequency deviation Aruba 10.7 + Australia 10.7 + ACS on 57 kHz (RDS) 67 kHz and below 95 kHz Bahamas Bangladesh (Peoples Republic of) 10.7 + Cyprus (Republic of) Vatican City State
36、Compression +10 dB Colombia (Republic of) 10.7 No SCA (67 kHz) Korea (Republic of) 10.7 + Optimod FM 8200 No Denmark 10.7 + EMC Yes RDS Ecuador 10.7 Spain 10.7 + RDS, SCA (67 kHz) United States of America 10.7 Not defined FCC 47 CFR 15 Optional RBDS (RDS), SCA Finland 10.7 + ORBAN compressor RDS Rec
37、. ITU-R BS.450-37TABLE 1b (continued) Information related to current receiving applications Additional information Oscillator position Country/Geographical area Recommended or used IF (MHz) High Low Electromagnetic immunity requirements for receivers Compressor or compander systems Supplementary inf
38、ormation Remarks France 10.7 + Yes, mainly for local radio RDS Synchronous frequency VHF-FM service for motorists in stereophonic mode along motorways. Frequency tolerance among all synchronous transmitters: 109Gambia (Republic of) 10.8 + Hungary (Republic of) 10.7 Not defined EN 55020, draft Hungar
39、ian standard ARI, RDS, SCA pilot, MBS India (Republic of) 10.7 + RDS, SCA (experimental transmissions) Iran (Islamic Republic of) 10.7 + No No RDS Italy 10.7 + Compressor of deviation control ISORADIO ISO frequency VHF-FM service for motorists in monophonic mode is introduced along the motorways Jap
40、an 10.7 + DARC Kuwat (State of) 10.7 + Lithuania (Republic of) 10.7 + Mali (Republic of) 10.7 Morocco (Kingdom of) 8Rec. ITU-R BS.450-3 TABLEAU 1b (end) Information related to current receiving applications Additional information Oscillator position Country/Geographical area Recommended or used IF (
41、MHz) High Low Electromagnetic immunity requirements for receivers Compressor or compander systems Supplementary information Remarks Norway 10.7 + Yes RDS New Zealand 10.7 + SCA use being developed 100-108 MHz presently used for domestic services Oman (Sultanate for) None None Papua New Guinea None N
42、one Netherlands (Kingdom of the) 10.7 Left to manufacturer Comply with EEC standards Yes RDS, CSI Qatar (State of) No Czech Republic 10.7 + Compression RDS United Kingdom of Great Britain and Northern Ireland 10.7 + REC, EEC EMC Directive; Radiation EN 55013; Immunity 55020 Yes RDS Rwandese Republic
43、 10.7 + Senegal (Republic of) 10.7 Singapore (Republic of) 10.7 + Optimod SCA Slovenia (Republic of) 10.7 + Yes RDS South Africa (Republic of) 10.7 + + No Optimod RDS, SST SST still on trial Sweden 10.7 + No Yes, audioprocessing (compression, limiter) RDS Switzerland (Confederation of) 10.7 + ARI, RDS Turkey 10.7 + No No No Ukraine 10.7
